Unique antiplatelet effects of a novel S-nitrosoderivative of a recombinant fragment of von Willebrand factor, AR545C: in vitro and ex vivo inhibition of platelet function.

摘要: The recombinant fragment of von Willebrand factor (vWF) spanning Ala444 to Asp730 and containing an Arg545Cys mutation (denoted AR545C) has antithrombotic properties that are principally a consequence its ability inhibit platelet adhesion subendothelial matrix. Endothelial-derived nitric oxide (NO) can also function, both as inhibiting well activation aggregation. Nitric react with thiol functional groups in the presence oxygen form S-nitrosothiols, which naturally occurring NO derivatives prolong biological actions NO. Because AR545C single free cysteine (Cys545), we attempted synthesize S-nitroso-derivative characterize antiplatelet effects. We successfully synthesized S-nitroso-AR545C found it contained 0.96 mol S-NO per mole peptide. was approximately 5-fold more potent at agglutination than unmodified peptide (IC50 = 0.02 ± 0.006 μmol/L v 0.1 0.03 μmol/L, P .001). In addition by contrast, powerful inhibitor adenosine diphosphate–induced aggregation 0.018 0.002 μmol/L), while had no effect on These effects were confirmed studies extracellular matrix under conditions shear stress cone-plate viscometer, where 1.5 inhibited 83% essentially completely aggregate formation, same concentration 74% significantly lesser formation ( ≤ .004 for each parameter ANOVA). ex vivo rabbit model, marked durable inhibitory botrocetin-induced did AR545C, these differences reflected extent duration prolongation bleeding time animals. data show significant unique effects, aggregation, blocking GPIb receptor through moiety elevating cyclic 3′,5′-guanosine monophosphate -SNO moiety. observations suggest this NO-modified vWF may have potential therapeutic benefits agent.